| SR Smart Repairs Limited | Wholesale & retail | 2011 |
| SRC Distribution Ltd | Wholesale & retail | 2024 |
| SRC Group Developments Limited | Construction | 2025 |
| SRC Group Holdings Limited | Real estate | 2017 |
| SRC Readymix Limited | Manufacturing | 2018 |
| Srcb Builders Limited | Construction | 2008 |
| Sreedeetya Solutions Limited | Information & communication | 2018 |
| SRI Karthikeya & Associates Limited | Health & social care | 2015 |
| SRI Lankan British Nursing and Midwifery Association CIC | Health & social care | 2023 |
| SRI Lankan Music Academy Ltd | Education | 2025 |
| Sriguru Limited | Information & communication | 2008 |
| Sringara Limited | Professional & scientific | 2017 |
| Sriram Ventures Limited | Real estate | 2024 |
| SRJ Cornerstone Limited | Real estate | 2022 |
| SRK Logics Limited | Real estate | 2020 |
| Srpinstallations Limited | Construction | 2017 |
| SRR Elite Cheerleading Ltd | Arts & recreation | 2025 |
| Srsg Limited | Real estate | 2019 |
| SRT Care Limited | Health & social care | 2018 |
| SRT Partnership Ltd | Information & communication | 2015 |
| SS Catering Essex Ltd | Hospitality | 2026 |
| SS Builders (Essex) Ltd | Construction | 2017 |
| SS Colchester Ltd | Professional & scientific | 2024 |
| SS Construction & Maintenance Limited | Construction | 2019 |
| Ssam Medical Ltd | Health & social care | 2025 |
| Ssas Experience Network Ltd | Administrative & support | 2024 |
| Sscp Pegasus Bidco Limited | Professional & scientific | 2020 |
| Sscp Pegasus Holdco Limited | Professional & scientific | 2020 |
| Sscp Pegasus Midco Limited | Professional & scientific | 2020 |
| Sscp Pegasus Topco Limited | Professional & scientific | 2020 |
| SSE Personal Assistant Provider Ltd | Health & social care | 2022 |
| SSG24 Security Ltd | Administrative & support | 2024 |
| Ssmb IT Solutions Limited | Information & communication | 2019 |
| SSR Technology Limited | Information & communication | 2025 |
| Ssrv Homes Limited | Real estate | 2024 |
| Sssl Group Ltd | Construction | 2018 |
| ST Annes Haulage (Essex) Limited | Wholesale & retail | 2006 |
| ST Benedict's Place (Snape) Management Company Limited | Households | 2016 |
| ST Dominic's Care Services Limited | Construction | 2020 |
| ST Edmunds Park (Hunstanton) Management Company Limited | Households | 2020 |
| ST Etienne Accommodation Limited | Real estate | 2017 |
| ST Gregory's Place Estate Management Company Limited | Households | 2017 |
| ST Gregory's Place Management Company Limited | Households | 2017 |
| ST Helena Care Services Ltd | Health & social care | 2020 |
| ST Helena Creative Services C.I.C. | Arts & recreation | 2023 |
| ST Helena Hospice Trading Limited | Wholesale & retail | 2010 |
| ST James (2) Management Company Limited | Households | 2005 |
| ST James Place (Management Company) Limited | Households | 2024 |
| ST James's Developments Limited | Real estate | 2007 |
| ST John's Green Playgroup Ltd | Education | 2010 |
| ST Mary Auto Engineering Ltd | Professional & scientific | 2018 |
| ST Marys Hall Farming Company Limited | Agriculture & fishing | 2013 |
| ST Peter's Court (Colchester) Management Company Limited | Professional & scientific | 1987 |
| ST Stephens Pre-School Community Interest Company | Administrative & support | 2016 |
| ST the Beauty Limited | Other services | 2023 |
| ST Wilfrids Care Home Ltd | Health & social care | 2015 |
| ST Wilfrids Development Company Limited | Real estate | 1998 |
| ST Wilfrids Hall Home Limited | Extraterritorial | 1998 |
| ST. Andrews Colchester Management Company Limited | Households | 1988 |
| ST. Dominics Residential Home Limited | Health & social care | 1994 |
| ST. Georges Court (Romford) Management Company Limited | Households | 2001 |
| ST. Georges Court (Romford) Management Company NO.2 Limited | Households | 2002 |
| ST. Giles Building Preservation Trust Limited | Arts & recreation | 2015 |
| ST. Giles Trustees Limited | Arts & recreation | 2015 |
| ST. Helena Mews Management Limited | Households | 1997 |
| ST. John's & Highwoods Community Association | Health & social care | 1996 |
| ST. Nicholas Court Management (Ipswich) Limited | Households | 2003 |
| ST. Osyth Investments Limited | Real estate | 1991 |
| St.Anne's Community Hall Association | Other services | 2007 |
| Stabilis Fitness Academy Ltd | Other services | 2013 |
| Stabilis Ventures Ltd | Professional & scientific | 2022 |
| Stable House (2017) Limited | Real estate | 2017 |
| Stacked Deck Productions Ltd. | Information & communication | 2012 |
| Stacy J Lake Consulting Ltd | Professional & scientific | 2019 |
| Staff Lisa Ltd | Health & social care | 2016 |
| Stag Advisor Support Ltd | Administrative & support | 2022 |
| Stag Clothing Ltd | Wholesale & retail | 2018 |
| Stage 2 Contracts Limited | Construction | 2014 |
| Stage Door Bar Ltd | Hospitality | 2022 |
| Stagecraft@Headgate Limited | Administrative & support | 2024 |
| Stagetext | Arts & recreation | 2000 |
| Stagg Engineering Ltd | Professional & scientific | 2024 |
| Stakd Food Ltd | Manufacturing | 2026 |
| Stalleys Property Service Ltd | Real estate | 2026 |
| Stan Builders Ltd | Manufacturing | 2024 |
| Stan Care Services Ltd | Health & social care | 2022 |
| Standard Leasing Limited | Professional & scientific | 1977 |
| Standbuild Construction Ltd | Construction | 2025 |
| Standon Hall Home Limited | Health & social care | 1999 |
| Standtech Systems Limited | Information & communication | 1998 |
| Standy Holdings Limited | Administrative & support | 2010 |
| Stane Park Ltd. | Real estate | 2001 |
| Stanfords Colchester LLP | | 2025 |
| Stanley Bragg Architects Ltd | Professional & scientific | 2010 |
| Stanley Park Road (Developments) Limited | Health & social care | 2014 |
| Stannard and SON Building Solutions Limited | Construction | 2019 |
| Stanway Automotive Limited | Wholesale & retail | 2016 |
| Stanway Building Solutions Ltd | Administrative & support | 2012 |
| Stanway Day Night Health Care Services Ltd | Health & social care | 2019 |
| Stanway DRY Cleaning Limited | Administrative & support | 2023 |